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Finding the Fourth Proportional to 138.38, 191.30 and 121.95

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Solution

The fourth proportional to 138.38, 191.30 and 121.95 is: 168.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.38 : 191.30 = 121.95 : x
  2. Step 2: Convert to fraction form
    138.38/191.30 = 121.95/x
  3. Step 3: Cross multiply
    138.38x = 191.30 × 121.95
  4. Step 4: Simplify right side
    138.38x = 23,328.43
  5. Step 5: Solve for x
    x = 23,328.43/138.38
  6. Step 6: Final answer
    x = 168.59

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.